Victim: Hannah Fryer bravely allowed this picture of her injuries to be used by cops (Image: Supplied)

Cops said the first offender is described as black, in his late 20s to early 30s, with short hair and stubble. He was wearing jeans, dark trainers and a distinctive patterned shirt.

There is no description of the second offender.

Constable Avril Gordon said: "These men subjected a young man and two young women to a vicious attack and left all three requiring treatment for facial injuries.

"So often we see attacks like this one end with more serious consequences, and it is sheer luck that these victims were left with injuries that did not require surgery or substantial stays in hospital.

Sickening: The20-year-old's injuries were extensive (Image: Supplied)

"One of the women assaulted, Hannah Fryer, was brave enough to ask us to issue a picture of her injuries to demonstrate the severity of this attack.

"The brutal and unprovoked nature of the incident means it is vitally important that we identify and locate the men responsible.

"We have an image of one of the men, and he is wearing quite a distinctive shirt so I hope there is someone out there who can recognise and identify him to us.

"Similarly, if you were in the area at the time of the attack and believe you can assist our investigation, please do not hesitate to contact us."

Anyone with information is asked to call police on 101 quoting incident number 171015/0296 or the independent charity Crimestoppers, anonymously, on 0800 555 111.